1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to transforming polarization, and more particularly, to transforming a certain incident polarized light into a polarized light having a predetermined polarization condition by controlling only one parameter with respect to the incident polarized light.
2. Description of the Related Art
An apparatus for transforming a light polarization is an apparatus that transforms an input optical signal into an optical signal having a predetermined polarization condition irrespective of the polarization condition of the input optical signal.
FIG. 1 is a block diagram of a conventional apparatus for transforming a light polarization disclosed in U.S. Pat. No. 5,191,387.
Referring to FIG. 1, the conventional polarization transforming apparatus 10 includes a first phase compensator 11 for compensating for a phase difference with respect to an incident light, a second phase compensator 12 for compensating for a phase difference by 45 degrees with respect to the light output from the first phase compensator 11, a polarized light rotator 13 for rotating a polarization plane of the light output from the second phase compensator 12, a beam splitter 14 for dividing the light of which the polarization plane is rotated, an analyzer 15 for analyzing the light output from the beam splitter 14, an light detector 16 for detecting the light output from the analyzer 15, and a controller 17 for controlling the polarized light rotator 14, the first and second phase compensators 11, 12 in response to the output of the light detector 16.
The polarization transforming apparatus shown FIG. 1 should control three parameters, i.e., a first phase reduction, second phase reduction and rotating angle, in order to continuously transform a certain incident polarized light into a polarized light having a desired polarization condition.
Since most conventional apparatuses for transforming the light polarization, including the apparatus 10 shown in FIG. 1, require many constituent parts and a complicated feedback control circuit in order to transform the incident polarized light into a polarized light having a predetermined polarization condition, their manufacturing costs are greatly increased.